Secondary closure



1967 R. w. EMMERT ETAL I 3,358,902

SECONDARY CLOSURE Filed June 24, 1966 INVENTORS. Robe/'1 W fmmerf BY wi/liamek. Park j mw zk AGENT United States Patent 3,358,902 SECONDARY CLOSURE Robert W. Emmert and William R. R. Park, Midland,

Mich, assignors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed June 24, 1966. Ser. No. 560,127 10 Claims. (Cl. 229-43) This invention relates to an improved secondary closure, and more particularly relates to an improved secondary closure which is readily detached from a package, and a method of applying such a closure.

Many varieties of secondary closures are employed in order to prevent opening and re-closure of packages such as bottles, jars, tubes and the like. Oftentimes, such a secondary closure has the form of a synthetic resinous tube which is shrunk about a portion of the package body and the primary closure in such a way that if the primary closure is dislodged or removed, the secondary closure is ruptured or deformed and a clear indication is obtained that the package has either been opened or an attempt has been made to open the package. Many of these secondary closures function well but are objectionable to the consumer in that frequently a tool such as a knife, can opener or other sharp instrument is required to initially rupture the secondary closure and permit ready removal of the primay closure.

It should be desirable if there were available an improved secondary closure which could readily be removed without the aid of tools.

It would be desirable if there were available an improved secondary closure which could be readily fabricated.

It would also be desirable if there were available an improved secondary closure which could be beat shrunk to conform to the primary closure of the container and provide a means of ready removal.

These benefits and other advantages in accordance with the present invention are achieved in a heat shrinkable secondary closure; the heat shrinkable secondary closure comprising an elongate strip of a heat shrinkable synthetic resinous thermoplasticmaterial; the strip having two generally parallel edges along first and second sides; the strip having a first end and a second end; the first end terminating in an edge generally normal to the direction of the sides; the second end having an edge defining an acute angle with one side of the strip and an obtuse angle with the remaining side of the strip; the first end and the second end of the strip being joined together wherein the edges of the first and second sides are in generally parallel relationship to form a generally circular configuration having an inner surface and an outer surface.

Also contemplated within the scope of the present invention is a method of applying a secondary closure to a container having a primary closure, the steps of the method comprising providing a heat shrinktable synthetic resinous thermoplastic material in the form of an elongate strip; the elongate strip having first and second side edges and first and second end edges; the first end edge of the strip being generally normal to the side edges; the second end edge forming an acute angle with one side and an obtuse angle with the remaining side, joining the first end of the strip to the second end of the strip while maintaining the end edges generally parallel; the edge of the strip meeting the second end edge at an obtuse angle forming a generally continuous edge, thereby forming a collar having a projecting point at the edge intersecting the end at an acute angle; heat shrinking the collar about at least the primary closure and an adjacent portion of the body of the container, thereby forming a tab from the material adjacent the second end edge and side edge forming the acute angle.

Further features and advantages of the present invention will become more apparent from the following specification taken in connection with the drawing wherein:

FIGURE 1 is a strip of shrinkable material for use in accordance with the invention.

FIGURE 2 is a representation of an unshrunken secondary closure in accordance with the invention disposed about a container.

FIGURE 3 is a top view of the container of FIGURE 2 after shrinking.

FIGURE 4 depicts an alternate embodiment of the invention.

In FIGURE 1 there is illustrated an elongate strip of synthetic resinous material generally designated by the reference numeral 10. The strip 10 is a heat shrinkable material having orientation at least in the direction indicated by the arrow. The strip 10 has a first side edge 11,

a second side edge 12. The side edges 11 and 12 are generally parallel to each other. The strip has a first end l4 having an end edge 15. The end edge 15 is generally normal to the side edges 11 and 12. A second end 16 is disposed remotely from the first end 14. The second end 16 has a second end edge 17 which is disposed at an acute angle 18 from the first edge 11 and at an obtuse angle 19 from the second side edge 12.

In FIGURE 2 there is depicted a representation of a container generally indicated by the reference numeral 25. The container 25 comprises a side Wall or body 26, a bottom 27 and a top or upper portion 28 having a secondary closure not shown. The strip 10 is disposed about the upper portion of the body 26 adjacent the secondary closure 28 in such a manner that the second edge 12 is disposed toward the bottom 27 of the container 25. The upper edge 11 projects above the top of the container. The first end 14 and second end 16 are disposed in adjacent relationship, and the first end edge 15 and the second end edge 17 are in generally parallel relationship. The first and second ends'14 and 16 are sealed together at the location 30. A tab 31 projects above'the edge 11 adjacent the first end 14. The second edge 12 forms a generally circular configuration.

In FIGURE 3 there is illustrated a top view of the container 25 after the strip 10 has been heat shrunk to form a secondary closure 10a. The secondary closure 10a has a first edge 11a, a second edge 120, a seal or joint 30a. A11 inwardly projecting tab 31a projects from the edge 11a of the first end 14a. The projecting tab 31a is readily grasped manually to remove the secondary closure and requires no tools. In FIGURE 3, the container 25 is shown as having a recessed primary closure 28 and the tab 31a is not in contact with the container. In instances where the primary closure does not have an edge ridge, the tab conforms generally to the configuration of the primary closure on shrinkage and yet is readily grasped by the user.

In FIGURE 4 there is depicted an alternate embodiment of the present invention generally designated by the reference numeral 40. The embodiment 40 comprises a container 41 having a bottom 42 and a top or primary closure 43. The container 41 has a side Wall 44. A secondary closure 45 generally similar to the secondary closure 10a of FIGURE 3 is disposed about the container in such a manner that it completely envelops the side wall 44 and projects inwardly over the bottom 42 and inwardly over the top 43 and defines a tab 46.

Beneficially, the secondary closures in accordance with the present invention are fabricated as separate loops, that is, the first and second ends are joined prior to positioning on the ends, or alternately, the strip may be passed about the container and maintained in position by heat sealing, ultrasonic sealing, adhesives and the like.

Any of a wide variety of synthetic resinous materials may be employed in forming secondary closures in accordance with the present invention. Such secondary closures advantageously may be fabricated from either biaxially oriented or monodirectionally oriented material. If the closures are fabricated from monoaxially oriented material, the direction of orientation should be such as to provide hoop stress on shrinking. The direction for beneficial maximum orientation is shown by the arrow in FIGURE 1. Among the suitable materials which may be employed for secondary closures in accordance with the present invention are oriented polyvinyl chloride, oriented sheet prepared by polymerizing a blend of 75 parts styrene and 25 parts of rubber, irradiated polyethylene, polypropylene, copolymers or vinylidene chloride with vinyl chloride, vinyl acetate or acrylate, oriented polycarbonates, oriented polyesters such as oriented polyethylene, glycol terephthalate and the like. Beneficially, shrinkage of the secondary closures may be accomplished by usual methods such as evposure to hot air at temperatures from about 200-350 F. for about 3 to 5 seconds.

As is apparent from the foregoing specification, the present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto-appended claims.

What is claimed is:

1. A heat shrinkable secondary closure, the closure comprising an elongate strip of a heat shrinkable synthetic resinous thermoplastic material, the strip having two generally parallel edges along first and second sides, the strip having a first end and a second end, the first end terminating in an edge generally normal to the direction of the sides, the second end having an edge defining an acute angle with one edge of the side of the strip and an obtuse angle with the remaining side of the strip, the first end and the second end of the strip being joined together wherein the edges of the first and second ends are in generally parallel relationship to form a generally circular configuration having an inner surface and an outer surface.

2. The secondary closure of claim 1 wherein the second side edge of the closure forms an obtuse angle with the second end edge of the strip and the second side edge forms a generally continuous circular configuration.

3. The econdary closure of claim 1 wherein the heat shrinkable thermoplastic material is molecularly oriented in the end-to-end direction.

4. The secondary closure of claim 1 wherein the first and second ends are heat sealed to each other.

5. The secondary closure of claim 1 disposed about a primary closure of a container in heat shrunken form wherein the second end edge defining an acute angle is disposed at the top of the container.

6. A method of applying a secondary closure to a container having a primary closure, the steps of the method comprising providing a heat shrinkable synthetic resinous thermoplastic material in the form of an elongate strip, the elongate strip having first and second side edges and first and second ends, the first end having a first end edge generally normal to the side edges, the second end having a second end edge forming an acute angle with one side and an obtuse angle with the remaining side, joining the first end of the strip to the second end of the strip to form a collar and a projecting point, heat shrinking the collar about at least the primary closure and an adjacent portion of the body of the container thereby forming a tab from the material adjacent the second end edge and the side edge forming the acute angle.

7. The method of claim 6 wherein the elongate strip has molecular orientation primarily in its major dimensron.

8. The method of claim 6 wherein the collar engages side walls of the container.

9. The method of claim 6 wherein the first end and the second end of the strip are joined by heat sealing.

10. The methd of claim 6 wherein the first end and the second end of the strip are joined by ultrasonic sealing.

References Cited UNITED STATES PATENTS 2,032,296 2/ 1936 Meier et al. 228-43 2,261,875 11/1941 Dunn 2l538 2,790,286 4/1957 Snyder 53-41 DONALD F. NORTON, Primary Examiner. 

1. A HEAT SHRINKABLE SECONDARY CLOSURE, THE CLOSURE COMPRISING AN ELONGATE STRIP OF A HEAT SHRINKABLE SYNTHETIC RESINOUS THERMOPLASTIC MATERIAL, THE STRIP HAVING TWO GENERALLY PARALLEL EDGES ALONG FIRST AND SECOND SIDES, THE STRIP HAVING A FIRST AND A SECOND END, THE FIRST END TERMINATING IN AN EDGE GENERALLY NORMAL TO THE DIRECTION OF THE SIDES, THE SECOND END HAVING AN EDGE DEFINING AN ACUTE ANGLE WITH ONE EDGE OF THE SIDE OF THE STRIP AND AN OBTUSE ANGLE WITH THE REMAINING SIDE OF THE STRIP, THE FIRST END AND THE SECOND END OF THE STRIP BEING JOINED TOGETHER WHEREIN THE EDGES OF THE FIRST AND SECOND ENDS ARE IN GENERALLY PARALLEL RELATIONSHIP TO FORM A GENERALLY CIRCULAR CONFIGURATION HAVING AN INNER SURFACE AND AN OUTER SURFACE. 